Betsey Fletcher is a character in Harlots played by Alexa Davies.
Underneath the grime, Betsey looks like an angel but she’s still tough as old boots. Betsey rents a room from Nancy Birch, works the streets to pay her way and is unlikely to rise any higher as she continues to drink away her profits.
Adorable young Betsey may looks like an angel with lovely blonde hair and blue eyes, but she is tough and spirited. As her review in Harris' List implies, Betsey is new to the trade and the town, "having been debauched not six months ago" and now frequents Russel Street.
She is fairly unpopular with culls, and spends most of her money on alcohol. In fact, she is only ever seen with one man, a Mr. Robert Oswald, who appears utterly infatuated. They frequently have sex is alley ways or street corners, which causes Oswald to lose his job when it's revealed he has a passion for prostitutes.
It is revealed by Violet Cross, who also had a room in Nancy's house and was friendly to Betsey (having once been seen sleeping in bed together, naked), in Season 2 that Oswald "fucked ... Betsey to the pox house." This suggests that poor Betsey contracted a venereal disease (probably syphilis or the "French Pox") and is now sick and dying. She is not mentioned again in the series.